Earlier quoted context omitted.
I've read that a handful of times (whenever trying to figure out where to put some new random thing), and still have never come to a clear conclusion. Even better, because there are so many similar places, you might choose completely different ones depending on the day of the week and your current mood. Too much choice for things like this is harmful IMO. Deep down I truly couldn't care less where the files end up, a…
It’s not just you: Every distro is its own special snowflake and patches the programs they distribute to store files in a different place. The “standard” doesn’t tell you what directory structure to use inside /etc to group related config files. The “standard” doesn’t tell you where an HTTP server should serve its files. Everyone just does their own thing which makes upstream docs incorrect and useless for newcomers.
The FHS, does actually answer both of of those questions. Files inside /etc/ should be grouped in subdirectories[0] andd the HTTP server should serve user-specified website files from /srv[1] and normal distro-provided files (such as the apache test page) from /var[2].
[0]: https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch03s07.htm...
[1]: https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch03s17.htm...
[2]: https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch05.html#p...